[mythtv-users] Converted MCE PC to MythTV - HDTV question

[Iohan Reyes]

OK, I tried XvMC, created /etc/X11/XvMCConfig and added one line:
libXvMCNVIDIA_dynamic.so.1

Then went into Mythfrontend Setup/TV Settings/Playback and changed
Preferred MPEG2 Decoder to Standard XvMC.  

It helped somewhat, CPU was lower but not drastically lower, went from
around 80-90% to around 60% utilization.  However, the stuttering is
still there and there are a bunch of "NVP: prebuffering pause" errors in
the logs.  I tried the suggestions in the "Tips and Tricks" section of
the Wiki page regarding XvMC and it still didn't help.

So I guess I am just out of luck and a Pentium IV 2.26ghz is just not
fast enough for HDTV?




-----Original Message-----
From: mythtv-users-bounces at mythtv.org
[mailto:mythtv-users-bounces at mythtv.org] On Behalf Of Kevin Kuphal
Sent: Sunday, November 05, 2006 3:26 PM
To: Discussion about mythtv
Subject: Re: [mythtv-users] Converted MCE PC to MythTV - HDTV question


>> To: Discussion about mythtv
>> Subject: Converted MCE PC to MythTV - HDTV question
>>
>> I had a fully-functioning MCE 2005 PC with the following relevant
specs:
>>
>> *	Pentium IV 2.26Ghz
>> *	2GB PC2700 RAM
>> *	320GB IDE Hard Drive
>> *	GeForce 6800GT 256MB -- Connected to a 15inch CRT monitor via
VGA and a BenQ PE8700 Front Projector via DVI.
>> *	MCE Remote
>> *	ATI HDTV Wonder
>>
>> Since I have built a few MythTV systems for use in different rooms of
my house, and this was the last remaining HTPC that wasn't MythTV, I
decided to reformat it and install FC5 + MythTV and add it as another
slave backend.  
>>
>> When this PC had Windows MCE 2005 on it, it could record and playback
HDTV just fine with no dropped frames.  I realize that there are major
underlying differences regarding drivers and the operating system
itself, but from everything I've been "conditioned" to believe is that
Linux is more efficient than Windows.  It therefore stands to reason (at
least in my mind, but of course, I've been wrong many times) that with
the exact same hardware underlying this new MythTV system, it should be
able to play HDTV without dropped frames.  Unfortunately, it seems like
I am mistaken and it looks like I need more CPU horsepower to make it
happen because now that I have finished setting up FC5 and MythTV, my
HDTV playback is dropping frames and looks herky jerky. I admit I
haven't researched too heavily yet since I just finished getting
everything working this morning, but I thought I would pose the question
here first.  
>>
>> Is there anything I can tweak to make HDTV smooth on my system given
the hardware I stated above?  Or am I asking too much out of my current
hardware and should instead upgrade my CPU/Motherboard/Memory?  I am
currently running nvidia-graphics8776 as my video card drivers for X.
Any tweaks there that can help?
>>
>> By the way, SD playback is fine, no problems whatsoever.
>>
>> Thanks for any and all help/suggestions you guys can provide.
>>     

The problem really lies in the hardware acceleration on the video card.

On Windows you're probably getting fully MPEG-2 playback acceleration.  
You can get that also on Linux assuming you can get XvMC working 
reliably.   Check out the wiki page on this:

http://www.mythtv.org/wiki/index.php/XvMC

Kevin

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